An annual bonus of 5-10% of your yearly salary is standard in a lot of industries, just as a 5-10% annual raise is considered standard. However, if you work on commission, you may see a significantly higher percentage. Your industry, company revenue, location, and level also heavily inform what's expected.
Bonuses may be awarded by a company as an incentive or to reward good performance. Typical incentive bonuses a company can give employees include signing, referral, and retention bonuses. Companies have various ways they can award employee bonuses, including cash, stock, and stock options.